Operating Segment and Sales and Credit Concentrations (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			3
Total revenues	$ 109,020	$ 150,484	$ 223,701	$ 326,664
Earnings from operations	22,150	35,974	44,065	76,671
Total Assets	1,460,358		1,460,358		$ 1,456,250
Corporate/Eliminations [Member]
Segment Reporting Information [Line Items]
Total Assets	(190,241)		(190,241)		(112,257)
Manufacturing [Member]
Segment Reporting Information [Line Items]
Total revenues	110,529	106,814	231,359	254,237
Earnings from operations	7,299	15,538	16,450	38,224
Total Assets	234,989		234,989		256,622
Railcar Leasing [Member]
Segment Reporting Information [Line Items]
Total revenues	33,717	33,209	67,552	65,977
Earnings from operations	18,690	20,237	37,500	39,912
Total Assets	1,354,037		1,354,037		1,254,824
Railcar Services [Member]
Segment Reporting Information [Line Items]
Total revenues	22,099	20,336	42,551	40,915
Earnings from operations	3,329	3,059	5,045	6,567
Total Assets	61,573		61,573		$ 57,061
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Earnings from operations	(4,953)	(4,441)	(9,225)	(8,949)
Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	(57,325)	(9,875)	(117,761)	(34,465)
Earnings from operations	(2,215)	1,581	(5,705)	917
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	109,020	150,484	223,701	326,664
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Total revenues	55,087	97,548	115,813	221,340
Operating Segments [Member] | Railcar Leasing [Member]
Segment Reporting Information [Line Items]
Total revenues	33,717	33,209	67,552	65,977
Operating Segments [Member] | Railcar Services [Member]
Segment Reporting Information [Line Items]
Total revenues	20,216	19,727	40,336	39,347
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Intersegment Eliminations [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Total revenues	55,442	9,266	115,546	32,897
Intersegment Eliminations [Member] | Railcar Leasing [Member]
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Intersegment Eliminations [Member] | Railcar Services [Member]
Segment Reporting Information [Line Items]
Total revenues	1,883	609	2,215	1,568
Intersegment Eliminations [Member] | Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	$ (57,325)	$ (9,875)	$ (117,761)	$ (34,465)